One dictionary's definition of a man is that a man is an adult male human being, as in "a tall man with a beard". A second definition says it refers to people of either sex, as in "goodwill to all men".
It is interesting, though, that the primary definition of a man focuses on physical or external features. If a man is a structure — beard, height, mustache, muscles, and so on — it's little wonder that manhood is often viewed by many as ruggedness that must be approved by the way you interact with others, whether by proving your road hog status or by abusing your spouses or by breaking laws in the interest of audacity as a bold adventurer.
It is interesting, though, that a "bwoy" in Jamaica is not always charcterised by physical stature, as sometimes fully grown men are termed bwoy if they appear timid to engage in robbery or some other nepharious activity.
So, obviously, those who view a man as a body expect more of him than just his physical appearance. But the expectations of a male often becomes twisted — a man possessing a strong body must prove himself by what such physical appearance represents — daredevil undertakings, gun-slinging adventures, robberies, road code violaters, and a slew of warped concepts of real manhood.
Even the ability to procreate and father many children with different women without supporting them is viewed as being a real man. So a man has had his own deviant and cultural nurturing, whereas a boy who says, "Please" or "Thank you" or allow women to go first is viewed as a sissy and as a "manto".
This external sizing up of an individual's external features has long put its mark on the value of colour, whereby children still keep alive expressions such as "black like tar" and "white an pretty".
This unfortunate view of a man or a woman's external characteristics has had devastating consequences, although science has proven racial neutrality among men or racial non-existence. More importantly, I think, are the words: "I now realise how true it is that God does not show favoritism but accepts from every nation the one who fears him and does what is right." (Acts 10:34 )